Highly viscous microemulsions based on sugar surfactants, oily bodies and aluminium salts and the use thereof in the production of anti-perspirant gel and stick preparations

ABSTRACT

A highly-viscous microemulsion containing: (a) a sugar surfactant; (b) an oil component; and (c) an aluminium-zirconium salt, and wherein the composition is transparent and has a Brookfield viscosity of at least about 100,000 mPas.

This application is a 371 of PCT/EP01/00986 filed Jan. 31, 2001.

BACKGROUND OF THE INVENTION

This invention relates generally to cosmetic emulsions and moreparticularly to high-viscosity microemulsions based on sugarsurfactants, oil components and aluminium-zirconium salts and to theiruse for the production of cosmetic gel and stick formulations.

Microemulsions are optically isotropic, thermodynamically stable systemswhich contain a water-insoluble oil component, emulsifiers and water.The clear or transparent appearance of microemulsions is a result of thesmall particle size of the dispersed emulsion droplets which, for themost part, is under 300 nm, fine-droplet microemulsions brown-red intransmitted light and a shimmering blue in reflected light occurring inthe 100 to 300 nm range and optically clear microemulsions occurring inthe sub-100 nm range. The droplet size of the macroemulsions is for themost part above 300 nm. By virtue of their greater stability in relationto macroemulsions, the finer distribution of the inner phase, theirgenerally greater effectiveness and the better transdermal penetrationof the active principles incorporated therein, microemulsions haveacquired considerable significance in the formulation of cosmetic andpharmaceutical preparations. However, their use in water-containingcosmetic gel and stick preparations which can be found on the market asantiperspirant or deodorant products requires a high consistency.Establishing the viscosity of such a system with long-chain polymersoften results in loss of the required transparency or in displacement ofthe thermodynamic equilibrium. Conventional thickeners, mainly polymers,leave the skin feeling sticky after application of the formulationscontaining them. In addition, antiperspirant or deodorant products areformulated at an acidic pH of ca. 4 and, to this end, require thickenersystems that are stable in this pH range, for example polydiols incombination with dibenzylidene sorbitol.

In addition, various antiperspirant sticks based on natural or syntheticwaxes in which the active substance is introduced into the wax matrix asa powder have been available on the market for many years. Thedisadvantage of such sticks is that they are very greasy and often leavea white residue on the skin.

The complex problem addressed by the present invention was to providehigh-viscosity microemulsions which would be distinguished bytransparency and high stability and which could be used asantiperspirant gel or stick formulations without the adverse sensoryeffects of large quantities of polymeric thickeners. Oily and aqueoussolutions would lend themselves to processing in the formulation,thereby simplifying homogeneous distribution.

DESCRIPTION OF THE INVENTION

The present invention relates to high-viscosity microemulsionscontaining

-   -   A) sugar surfactants,    -   B) oil components and    -   C) aluminium-zirconium salts.

It has surprisingly been found that the combination of sugarsurfactants, oil components and aluminium-zirconium salts leads to cleartransparent microemulsions with viscosities of at least 100,000 mPas,preferably 400,000 mPas and more particularly 800,000 to 3,000,000 mPas.

Besides their stability and transparency, the formulations according tothe invention have a consistency which enables them to be processed intogels or sticks. Conventional polymeric thickeners, which are attended bythe disadvantage that they leave the skin feeling sticky, can be reducedor even avoided altogether. Oily and aqueous solutions can be processedin the formulation so that homogeneous distribution is simplified.

Sugar Surfactants

Sugar surfactants are surface-active substances based on carbohydrateswhich include, for example, sugar esters, sorbitan esters andpolysorbates, alkyl oligoglucosides and fatty acid glucamides. Sugaresters are esters of mono- and oligosaccharides and—in the broadersense—of sugar alcohols with organic and inorganic acids. Industriallythe most important sugar esters are the mono- and diesters of thesugars, more especially sucrose, with higher fatty acids, such aslauric, myristic, palmitic, stearic or oleic acid or with tallow fattyacids. These sugar esters have pronounced surface-active properties [cf.Römpp Lexikon Chemie—Version 2.0, Stuttgart/New York; Georg ThiemeVerlag 1999]. Sorbitan esters are mono-, di- and triesters of thesorbitans with fatty acids. Sorbitan esters and their ethoxylatedderivatives (polysorbates) are used as particularly environmentally safenonionic surfactants in the cosmetics, pharmaceutical and foodindustries [cf. J. Am. Oil Chem. Soc. 66, 1581 (1989), Tenside Surf.Deterg. 27, 350 (1990)].

Alkyl and/or Alkenyl Oligoglycosides

Alkyl and alkenyl oligoglycosides suitable as emulsifier component areknown nonionic surfactants which correspond to general formula (I):R¹O-[G]_(p)  (I)where R¹ is an alkyl and/or alkenyl group containing 4 to 22 carbonatoms, G is a sugar unit containing 5 or 6 carbon atoms and p is anumber of 1 to 10. They may be obtained by the relevant methods ofpreparative organic chemistry. EP-A1-0 301 298 and WO 90/03977 are citedas representative of the extensive literature available on this subject.

The alkyl and/or alkenyl oligoglycosides may be derived from aldoses orketoses containing 5 or 6 carbon atoms, preferably glucose. The index pin general formula (I) indicates the degree of oligomerization (DP),i.e. the distribution of mono- and oligoglycosides, and is a number of 1to 10. Whereas p in a given compound must always be an integer and,above all, may assume a value of 1 to 6, the value p for a certain alkyloligoglycoside is an analytically determined calculated quantity whichis generally a broken number. Alkyl and/or alkenyl oligoglycosideshaving an average degree of oligomerization p of 1.1 to 3.0 arepreferably used. Alkyl and/or alkenyl oligoglycosides having a degree ofoligomerization of less than 1.7 and, more particularly, between 1.2 and1.4 are preferred from the applicational point of view.

The alkyl or alkenyl group R¹ may be derived from primary alcoholscontaining 4 to 11 and preferably 8 to 10 carbon atoms. Typical examplesare butanol, caproic alcohol, caprylic alcohol, capric alcohol andundecyl alcohol and the technical mixtures thereof obtained, forexample, in the hydrogenation of technical fatty acid methyl esters orin the hydrogenation of aldehydes from Roelen's oxosynthesis. Alkyloligoglucosides having a chain length of C₈ to C₁₀ (DP=1 to 3), whichare obtained as first runnings in the separation of technical C₈₋₁₈coconut oil fatty alcohol by distillation and which may contain lessthan 6% by weight of C₁₂ alcohol as an impurity, and also alkyloligoglucosides based on technical C_(9/11) oxoalcohols (DP=1 to 3) arepreferred. In addition, the alkyl or alkenyl group R¹ may also bederived from primary alcohols containing 12 to 22 and preferably 12 to14 carbon atoms. Typical examples are lauryl alcohol, myristyl alcohol,cetyl alcohol, palmitoleyl alcohol, stearyl alcohol, isostearyl alcohol,oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, arachyl alcohol,gadoleyl alcohol, behenyl alcohol, erucyl alcohol, brassidyl alcohol andtechnical mixtures thereof which may be obtained as described above.Alkyl oligoglucosides based on hydrogenated C_(12/14) coconut oil fattyalcohol having a DP of 1 to 3 are preferred.

Fatty acid-N-alkyl Polyhydroxyalkylamides

Fatty acid-N-alkyl polyhydroxyalkylamides are nonionic surfactantscorresponding to formula (II):

in which R²CO is an aliphatic acyl group containing 6 to 22 carbonatoms, R³ is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4carbon atoms and [Z] is a linear or branched polyhydroxyalkyl groupcontaining 3 to 12 carbon atoms and 3 to 10 hydroxyl groups. The fattyacid-N-alkyl polyhydroxyalkylamides are known compounds which maynormally be obtained by reductive amination of a reducing sugar withammonia, an alkylamine or an alkanolamine and subsequent acylation witha fatty acid, a fatty acid alkyl ester or a fatty acid chloride.Processes for their production are described in U.S. Pat. No. 1,985,424,in U.S. Pat. No. 2,016,962 and in U.S. Pat. No. 2,703,798 and inInternational patent application WO 92/06984. An overview of thissubject by H. Kelkenberg can be found in Tens. Surf. Det. 25, 8 (1988).

The fatty acid-N-alkyl polyhydroxyalkylamides are preferably derivedfrom reducing sugars containing 5 or 6 carbon atoms, more particularlyfrom glucose. Accordingly, the preferred fatty acid-N-alkylpolyhydroxyalkylamides are fatty acid-N-alkyl glucamides whichcorrespond to formula (III):

Preferred fatty acid-N-alkyl polyhydroxyalkylamides are glucamidescorresponding to formula (III) in which R³ is hydrogen or an alkyl groupand R²CO represents the acyl component of caproic acid, caprylic acid,capric acid, lauric acid, myristic acid, palmitic acid, palmitoleicacid, stearic acid, isostearic acid, oleic acid, elaidic acid,petroselic acid, linoleic acid, linolenic acid, arachic acid, gadoleicacid, behenic acid or erucic acid or technical mixtures thereof. Fattyacid-N-alkyl glucamides (III) obtained by reductive amination of glucosewith methylamine and subsequent acylation with lauric acid or C_(12/14)coconut oil fatty acid or a corresponding derivative are particularlypreferred. In addition, the polyhydroxyalkylamides may also be derivedfrom maltose and palatinose.Oil Components

Suitable oil components are, for example, Guerbet alcohols based onfatty alcohols containing 6 to 18 and preferably 8 to 10 carbon atoms,esters of linear C₆₋₂₂ fatty acids with linear C₆₋₂₂ fatty alcohols,esters of branched C₆₋₁₃ carboxylic acids with linear C₆₋₂₂ fattyalcohols such as, for example, myristyl myristate, myristyl palmitate,myristyl stearate, myristyl isostearate, myristyl oleate, myristylbehenate, myristyl erucate, cetyl myristate, cetyl palmitate, cetylstearate, cetyl isostearate, cetyl oleate, cetyl behenate, cetylerucate, stearyl myristate, stearyl palmitate, stearyl stearate, stearylisostearate, stearyl oleate, stearyl behenate, stearyl erucate,isostearyl myristate, isostearyl palmitate, isostearyl stearate,isostearyl isostearate, isostearyl oleate, isostearyl behenate,isostearyl oleate, oleyl myristate, oleyl palmitate, oleyl stearate,oleyl isostearate, oleyl oleate, oleyl behenate, oleyl erucate, behenylmyristate, behenyl palmitate, behenyl stearate, behenyl isostearate,behenyl oleate, behenyl behenate, behenyl erucate, erucyl myristate,erucyl palmitate, erucyl stearate, erucyl isostearate, erucyl oleate,erucyl behenate and erucyl erucate. Also suitable are esters of linearC₆₋₂₂ fatty acids with branched alcohols, more particularly 2-ethylhexanol, esters of C₁₈₋₃₈ alkylhydroxy-carboxylic acids with linear orbranched C₆₋₂₂ fatty alcohols (cf. DE 197 56 377 A1), more especiallyDioctyl Malate, esters of linear and/or branched fatty acids withpolyhydric alcohols (for example propylene glycol, dimer diol or trimertriol) and/or Guerbet alcohols, triglycerides based on C₆₋₁₀ fattyacids, liquid mono-, di- and triglyceride mixtures based on C₆₋₁₈ fattyacids, esters of C₆₋₂₂ fatty alcohols and/or Guerbet alcohols witharomatic carboxylic acids, more particularly benzoic acid, esters ofC₂₋₁₂ dicarboxylic acids with linear or branched alcohols containing 1to 22 carbon atoms or polyols containing 2 to 10 carbon atoms and 2 to 6hydroxyl groups, vegetable oils, branched primary alcohols, substitutedcyclohexanes, linear and branched C₆₋₂₂ fatty alcohol carbonates,Guerbet carbonates, esters of benzoic acid with linear and/or branchedC₆₋₂₂ alcohols (for example Finsolv® TN), linear or branched,symmetrical or nonsymmetrical dialkyl ethers containing 6 to 22 carbonatoms per alkyl group, ring opening products of epoxidized fatty acidesters with polyols, silicone oils (cyclomethicone, silicon methiconetypes, etc.) and/or aliphatic or naphthenic hydrocarbons, for examplesqualane, squalene or dialkyl cyclohexanes, dialkyl carbonatescorresponding to formula (IV):

in which R¹ is a linear alkyl and/or alkenyl group containing 6 to 22carbon atoms, a 2-ethylhexyl, isotridecyl or isostearyl group or a groupderived from a polyol containing 2 to 15 carbon atoms and at least twohydroxyl groups, R² has the same meaning as R¹ or is an alkyl groupcontaining 1 to 5 carbon atoms and n and m independently of one anotherrepresent 0 or numbers of 1 to 100, preferably dioctyl carbonate.Aluminium-zirconium Salts

Salts of aluminium, zirconium or zinc are used as astringentantiperspirants. Aluminium-zirconium salts in particular aredistinguished by good antihydrotic activity. They are preferably complexcompounds of amino acids, for example glycine, with chlorohydrate saltsof the metals aluminium and zirconium in an Al:Zr ratio of 3 to 10:1(ratio of metals to chloride 0.9 to 2.1:1). Aluminium-zirconiumtrichlorohydrate, aluminium-zirconium tetrachlorohydrate,aluminium-zirconium pentachlorohydrate, aluminium-zirconiumoctachlorohydrate are preferably used in cosmetic formulations.

Thickeners

Suitable thickeners are, for example, polysaccharides, more especiallyxanthan gum, guar-guar, agar-agar, alginates and tyloses, carboxymethylcellulose and hydroxyethyl cellulose, also relatively high molecularweight polyethylene glycol monoesters and diesters of fatty acids,polyacrylates, polyvinyl alcohol and polyvinyl pyrrolidone, surfactantssuch as, for example, ethoxylated fatty acid glycerides, esters of fattyacids with polyols, for example pentaerythritol or trimethylol propane,narrow-range fatty alcohol ethoxylates or alkyl oligoglucosides andelectrolytes, such as sodium chloride and ammonium chloride. However,the advantage of the formulation according to the invention is that thequantities of thickeners used can be reduced. If only 2% m/m thickeneris added to the formulation according to the invention, an increase inviscosity of up to at least 2,000,000 mPas and preferably between2,000,000 and 3,000,000 mPas is achieved.

Co-emulsifiers

To prepare microemulsions, sugar surfactants are used in combinationwith co-emulsifiers of which partial glycerides are preferably used. Theratio of sugar surfactants to partial glycerides should be in the rangefrom 10:90 to 90:10, preferably in the range from 20:80 to 80:20 andmore particularly in the range from 40:60 to 60:40.

Suitable co-emulsifiers are, for example, nonionic surfactants from atleast one of the following groups:

-   -   products of the addition of 2 to 30 mol ethylene oxide and/or 0        to 5 mol propylene oxide onto linear fatty alcohols containing 8        to 22 carbon atoms, onto fatty acids containing 12 to 22 carbon        atoms and onto alkylphenols containing 8 to 15 carbon atoms in        the alkyl group;    -   C_(12/18) fatty acid monoesters and diesters of products of the        addition of 1 to 30 mol ethylene oxide onto glycerol;    -   glycerol monoesters and diesters of saturated and unsaturated        fatty acids containing 6 to 22 carbon atoms and ethylene oxide        adducts thereof;    -   products of the addition of 15 to 60 mol ethylene oxide onto        castor oil and/or hydrogenated castor oil;    -   polyol esters and, in particular, polyglycerol esters such as,        for example, polyglycerol polyricinoleate or polyglycerol        poly-12-hydroxy-stearate. Mixtures of compounds from several of        these classes are also suitable;    -   products of the addition of 2 to 15 mol ethylene oxide onto        castor oil and/or hydrogenated castor oil;    -   partial esters based on linear, branched, unsaturated or        saturated C_(12/22) fatty acids, ricinoleic acid and        12-hydroxystearic acid and glycerol, polyglycerol,        pentaerythritol, dipentaerythritol;    -   trialkyl phosphates;    -   wool wax alcohols;    -   polysiloxane/polyalkyl polyether copolymers and corresponding        derivatives;    -   mixed esters of pentaerythritol, fatty acids, citric acid and        fatty alcohol according to DE 1165574 PS and    -   polyalkylene glycols;    -   mono-, di- and trialkyl phosphates and mono-, di- and/or        tri-PEG-alkyl phosphates and salts thereof;    -   block copolymers, for example Polyethyleneglycol-30        Dipolyhydroxystearate;    -   polymer emulsifiers, for example Pemulen types (TR-1, TR-2) from        Goodrich;    -   glycerol carbonate.

The addition products of ethylene oxide and/or propylene oxide ontofatty alcohols, fatty acids, alkylphenols or onto castor oil are knowncommercially available products. They are homolog mixtures of which theaverage degree of alkoxylation corresponds to the ratio between thequantities of ethylene oxide and/or propylene oxide and substrate withwhich the addition reaction is carried out. C_(12/18) fatty acidmonoesters and diesters of adducts of ethylene oxide with glycerol areknown as refatting agents for cosmetic formulations from DE 20 24 051PS.

Typical examples of suitable partial glycerides are hydroxystearic acidmonoglyceride, hydroxystearic acid diglyceride, isostearic acidmonoglyceride, isostearic acid diglyceride, oleic acid monoglyceride,oleic acid diglyceride, ricinoleic acid monoglyceride, ricinoleic aciddiglyceride, linoleic acid monoglyceride, linoleic acid diglyceride,linolenic acid monoglyceride, linolenic acid diglyceride, erucic acidmonoglyceride, erucic acid diglyceride, tartaric acid monoglyceride,tartaric acid diglyceride, citric acid monoglyceride, citric aciddiglyceride, malic acid monoglyceride, malic acid diglyceride andtechnical mixtures thereof which may still contain small quantities oftriglyceride from the production process. Addition products of 1 to 30and preferably 5 to 10 mol ethylene oxide onto the partial glyceridesmentioned are also suitable.

Typical examples of suitable polyglycerol esters are Polyglyceryl-2Dipolyhydroxystearate (Dehymuls® PGPH), Polyglycerin-3 Diisostearate(Lameform® TGI), Polyglyceryl-4 Isostearate (Isolan® GI 34),Polyglyceryl-3 Oleate, Diisostearoyl Polyglyceryl-3 Diisostearate(Isolan® PDI), Polyglyceryl-3 Methylglucose Distearate (Tego Care® 450),Polyglyceryl-3 Beeswax (Cera Bellina®), Polyglyceryl-4 Caprate(Polyglycerol Caprate T2010/90), Polyglyceryl-3 Cetyl Ether (Chimexane®NL), Polyglyceryl-3 Distearate (Cremophor® GS 32) and PolyglycerylPolyricinoleate (Admul® WOL 1403), Polyglyceryl Dimerate Isostearate andmixtures thereof. Examples of other suitable polyolesters are the mono-,di- and triesters of trimethylolpropane or pentaerythritol with lauricacid, cocofatty acid, tallow fatty acid, palmitic acid, stearic acid,oleic acid, behenic acid and the like optionally reacted with 1 to 30moles of ethylene oxide.

The preparations may also contain fatty alcohols as an additionalcomponent with co-emulsifying properties. Fatty alcohols in the contextof the invention are understood to be primary aliphatic alcohols, suchas caproic alcohol, caprylic alcohol, 2-ethylhexyl alcohol, capricalcohol, lauryl alcohol, isotridecyl alcohol, myristyl alcohol, cetylalcohol, palmitoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleylalcohol, elaidyl alcohol, petroselinyl alcohol, linolyl alcohol,linolenyl alcohol, elaeostearyl alcohol, arachyl alcohol gadolylalcohol, behenyl alcohol, erucyl alcohol and brassidyl alcohol, and thetechnical mixtures thereof obtained, for example in the high-pressurehydrogenation of technical methyl esters based on fats and oils oraldehydes from Roelen's oxosynthesis and as monomer fraction in thedimerization of unsaturated fatty alcohols. Technical fatty alcoholscontaining 12 to 18 carbon atoms, such as coconut fatty alcohol forexample, are preferred. The fatty alcohols may make up from 1 to 35% byweight and preferably from 5 to 30% by weight of the preparations.

Alternatively, diols may also be used. Typical examples aredodecane-1,12-diol, hexadecane-1,16-diol, 12-hydroxystearyl alcohol andring opening products of epoxidized C₆₋₂₂ olefins with water or polyols,preferably glycerol. The diols may make up from 1 to 35% by weight andpreferably from 5 to 30% by weight of the preparations.

Other suitable emulsifiers are zwitterionic surfactants. Zwitterionicsurfactants are surface-active compounds which contain at least onequaternary ammonium group and at least one carboxylate and one sulfonategroup in the molecule. Particularly suitable zwitterionic surfactantsare the so-called betaines, such as the N-alkyl-N,N-dimethyl ammoniumglycinates, for example cocoalkyl dimethyl ammonium glycinate,N-acylaminopropyl-N,N-dimethyl ammonium glycinates, for examplecocoacylaminopropyl dimethyl ammonium glycinate, and2-alkyl-3-carboxymethyl-3-hydroxyethyl imidazolines containing 8 to 18carbon atoms in the alkyl or acyl group and cocoacylaminoethylhydroxyethyl carboxymethyl glycinate. The fatty acid amide derivativeknown under the CTFA name of Cocamidopropyl Betaine is particularlypreferred. Ampholytic surfactants are also suitable emulsifiers.Ampholytic surfactants are surface-active compounds which, in additionto a C_(8/18) alkyl or acyl group, contain at least one free amino groupand at least one —COOH or —SO₃H group in the molecule and which arecapable of forming inner salts. Examples of suitable ampholyticsurfactants are N-alkyl glycines, N-alkyl propionic acids,N-alkylaminobutyric acids, N-alkyliminodipropionic acids,N-hydroxyethyl-N-alkylamidopropyl glycines, N-alkyl taurines, N-alkylsarcosines, 2-alkylaminopropionic acids and alkylaminoacetic acidscontaining around 8 to 18 carbon atoms in the alkyl group. Particularlypreferred ampholytic surfactants are N-cocoalkylaminopropionate,cocoacylaminoethyl aminopropionate and C_(12/18) acyl sarcosine. Besidesampholytic emulsifiers, quaternary emulsifiers may also be used, thoseof the esterquat type, preferably methyl-quaternized difatty acidtriethanolamine ester salts, being particularly preferred.

COMMERCIAL APPLICATIONS

High-viscosity microemulsions may be used in cosmetic gel and stickformulations used as antiperspirants. Antiperspirants are cosmeticformulations which reduce perspiration and hence underarm wetness byinfluencing the activity of the eccrine sweat glands and whichcontribute to a reduction of body odor. Hitherto, antiperspirants havepreferably been formulated as water-free suspensions or aswater-containing solutions or emulsions. Given a suitably highviscosity, however, the microemulsions according to the invention may bedirectly used for processing into gels or sticks. Typically they havethe following composition:

-   -   A) 1-40% m/m, preferably 10-30% m/m and more particularly 15-20%        m/m sugar surfactants,    -   B) 10-50% m/m, preferably 18-35% m/m and more particularly        20-25% m/m oil components,    -   C) 5-40% m/m, preferably 10-30% m/m and more particularly 15-20%        m/m aluminium-zirconium salts,    -   D) 0-10% m/m, preferably 1-8% m/m and more particularly 2-5% m/m        thickeners,        with the proviso that the quantities shown add up to 100% m/m,        optionally with water and/or other typical auxiliaries and        additives.

The preparations according to the invention may contain superfattingagents, fats, waxes, lecithins, phospholipids, biogenic agents,antioxidants, solubilizers, preservatives, perfume oils, dyes and thelike as further auxiliaries and additives.

Fats and Waxes

Typical examples of fats are glycerides, i.e. solid or liquid, vegetableor animal products which consist essentially of mixed glycerol esters ofhigher fatty acids. Suitable waxes are inter alia natural waxes such as,for example, candelilla wax, carnauba wax, Japan wax, espartograss wax,cork wax, guaruma wax, rice germ oil wax, sugar cane wax, ouricury wax,montan wax, beeswax, shellac wax, spermaceti, lanolin (wool wax),uropygial fat, ceresine, ozocerite (earth wax), petrolatum, paraffinwaxes and microwaxes; chemically modified waxes (hard waxes) such as,for example, montan ester waxes, sasol waxes, hydrogenated jojoba waxesand synthetic waxes such as, for example, polyalkylene waxes andpolyethylene glycol waxes. Besides the fats, other suitable additivesare fat-like substances, such as lecithins and phospholipids. Lecithinsare known among experts as glycerophospholipids which are formed fromfatty acids, glycerol, phosphoric acid and choline by esterification.Accordingly, lecithins are also frequently referred to by experts asphosphatidyl cholines (PCs) and correspond to general formula (V):

where R typically represents linear aliphatic hydrocarbon radicalscontaining 15 to 17 carbon atoms and up to 4 cis-double bonds. Examplesof natural lecithins are the kephalins which are also known asphosphatidic acids and which are derivatives of1,2-diacyl-sn-glycerol-3-phosphoric acids. By contrast, phospholipidsare generally understood to be mono- and preferably diesters ofphosphoric acid with glycerol (glycerophosphates) which are normallyclassed as fats. Sphingosines and sphingolipids are also suitable.Superfatting Agents

Superfatting agents may be selected from such substances as, forexample, lanolin and lecithin and also polyethoxylated or acylatedlanolin and lecithin derivatives, polyol fatty acid esters,monoglycerides and fatty acid alkanolamides, the fatty acidalkanolamides also serving as foam stabilizers.

Antioxidants

Typical examples of suitable antioxidants are amino acids (for exampleglycine, histidine, tyrosine, tryptophane) and derivatives thereof,imidazoles (for example urocanic acid) and derivatives thereof,peptides, such as D,L-carnosine, D-carnosine, L-carnosine andderivatives thereof (for example anserine), carotinoids, carotenes (forexample α-carotene, β-carotene, lycopene) and derivatives thereof,chlorogenic acid and derivatives thereof, liponic acid and derivativesthereof (for example dihydroliponic acid), aurothioglucose,propylthiouracil and other thiols (for example thioredoxine,glutathione, cysteine, cystine, cystamine and glycosyl, N-acetyl,methyl, ethyl, propyl, amyl, butyl and lauryl, palmitoyl, oleyl,γ-linoleyl, cholesteryl and glyceryl esters thereof) and their salts,dilaurylthiodipropionate, distearylthiodipropionate, thiodipropionicacid and derivatives thereof (esters, ethers, peptides, lipids,nucleotides, nucleosides and salts) and sulfoximine compounds (forexample butionine sulfoximines, homocysteine sulfoximine, butioninesulfones, penta-, hexa- and hepta-thionine sulfoximine) in very smallcompatible dosages (for example pmol to μmol/kg), also (metal) chelators(for example α-hydroxyfatty acids, palmitic acid, phytic acid,lactoferrine), α-hydroxy acids (for example citric acid, lactic acid,malic acid), humic acid, bile acid, bile extracts, bilirubin,biliverdin, EDTA, EGTA and derivatives thereof, unsaturated fatty acidsand derivatives thereof (for example γ-linolenic acid, linoleic acid,oleic acid), folic acid and derivatives thereof, ubiquinone andubiquinol and derivatives thereof, vitamin C and derivatives thereof(for example ascorbyl palmitate, Mg ascorbyl phosphate, ascorbylacetate), tocopherols and derivatives (for example vitamin E acetate),vitamin A and derivatives (vitamin A palmitate) and coniferyl benzoateof benzoin resin, rutinic acid and derivatives thereof, α-glycosylrutin, ferulic acid, furfurylidene glucitol, carnosine, butylhydroxytoluene, butyl hydroxyanisole, nordihydroguaiac resin acid,nordihydroguaiaretic acid, trihydroxy-butyrophenone, uric acid andderivatives thereof, mannose and derivatives thereof,Superoxid-Dismutase, zinc and derivatives thereof (for example ZnO,ZnSO₄), selenium and derivatives thereof (for example seleniummethionine), stilbenes and derivatives thereof (for example stilbeneoxide, trans-stilbene oxide) and derivatives of these active substancessuitable for the purposes of the invention (salts, esters, ethers,sugars, nucleotides, nucleosides, peptides and lipids).

Biogenic Agents

In the context of the invention, biogenic agents are, for example,tocopherol, tocopherol acetate, tocopherol palmitate, ascorbic acid,deoxyribonucleic acid, retinol, bisabolol, allantoin, phytantriol,panthenol, AHA acids, amino acids, ceramides, pseudoceramides, essentialoils, plant extracts and vitamin complexes.

Deodorants and Germ Inhibitors

Cosmetic deodorants counteract, mask or eliminate body odors. Body odorsare formed through the action of skin bacteria on apocrine perspirationwhich results in the formation of unpleasant-smelling degradationproducts. Accordingly, deodorants contain active principles which act asgerm inhibitors, enzyme inhibitors, odor absorbers or odor maskers.Basically, suitable germ inhibitors are any substances which act againstgram-positive bacteria such as, for example, 4-hydroxybenzoic acid andsalts and esters thereof,N-(4-chlorophenyl)-N′-(3,4-dichlorophenyl)-urea,2,4,4′-trichloro-2′-hydroxydiphenylether (triclosan),4-chloro-3,5-dimethylphenol,2,2′-methylene-bis-(6-bromo-4-chlorophenol),3-methyl-4-(1-methylethyl)-phenol, 2-benzyl-4-chlorophenol,3-(4-chlorophenoxy)-propane-1,2-diol, 3-iodo-2-propinyl butyl carbamate,chlorhexidine, 3,4,4′-trichlorocarbanilide (TTC), antibacterialperfumes, thymol, thyme oil, eugenol, clove oil, menthol, mint oil,farnesol, phenoxyethanol, glycerol monocaprate, glycerol monocaprylate,glycerol monolaurate (GML), diglycerol monocaprate (DMC), salicylicacid-N-alkylamides such as, for example, salicylic acid-n-octyl amide orsalicylic acid-n-decyl amide.

Suitable enzyme inhibitors are, for example, esterase inhibitors.Esterase inhibitors are preferably trialkyl citrates, such as trimethylcitrate, tripropyl citrate, triisopropyl citrate, tributyl citrate and,in particular, triethyl citrate (Hydagen® CAT, Cognis GmbH, Dusseldorf,FRG). Esterase inhibitors inhibit enzyme activity and thus reduce odorformation. Other esterase inhibitors are sterol sulfates or phosphatessuch as, for example, lanosterol, cholesterol, campesterol, stigmasteroland sitosterol sulfate or phosphate, dicarboxylic acids and estersthereof, for example glutaric acid, glutaric acid monoethyl ester,glutaric acid diethyl ester, adipic acid, adipic acid monoethyl ester,adipic acid diethyl ester, malonic acid and malonic acid diethyl ester,hydroxycarboxylic acids and esters thereof, for example citric acid,malic acid, tartaric acid or tartaric acid diethyl ester, and zincglycinate.

Suitable odor absorbers are substances which are capable of absorbingand largely retaining the odor-forming compounds. They reduce thepartial pressure of the individual components and thus also reduce therate at which they spread. An important requirement in this regard isthat perfumes must remain unimpaired. Odor absorbers are not activeagainst bacteria. They contain, for example, a complex zinc salt ofricinoleic acid or special perfumes of largely neutral odor known to theexpert as “fixateurs” such as, for example, extracts of ladanum orstyrax or certain abietic acid derivatives as their principal component.Odor maskers are perfumes or perfume oils which, besides theirodor-masking function, impart their particular perfume note to thedeodorants. Suitable perfume oils are, for example, mixtures of naturaland synthetic perfumes. Natural perfumes include the extracts ofblossoms, stems and leaves, fruits, fruit peel, roots, woods, herbs andgrasses, needles and branches, resins and balsams. Animal raw materials,for example civet and beaver, may also be used. Typical syntheticperfume compounds are products of the ester, ether, aldehyde, ketone,alcohol and hydrocarbon type. Examples of perfume compounds of the estertype are benzyl acetate, p-tert.butyl cyclohexylacetate, linalylacetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, allylcyclohexyl propionate, styrallyl propionate and benzyl salicylate.Ethers include, for example, benzyl ethyl ether while aldehydes include,for example, the linear alkanals containing 8 to 18 carbon atoms,citral, citronellal, citronellyloxyacetaldehyde, cyclamen aldehyde,hydroxy-citronellal, lilial and bourgeonal. Examples of suitable ketonesare the ionones and methyl cedryl ketone. Suitable alcohols are anethol,citronellol, eugenol, isoeugenol, geraniol, linalool, phenylethylalcohol and terpineol. The hydrocarbons mainly include the terpenes andbalsams. However, it is preferred to use mixtures of different perfumecompounds which, together, produce an agreeable fragrance. Othersuitable perfume oils are essential oils of relatively low volatilitywhich are mostly used as aroma components. Examples are sage oil,camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil,lime-blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanumoil, ladanum oil and lavendin oil. The following are preferably usedeither individually or in the form of mixtures: bergamot oil,dihydromyrcenol, lilial, lyral, citronellol, phenylethyl alcohol,α-hexylcinnamaldehyde, geraniol, benzyl acetone, cyclamen aldehyde,linalool, Boisambrene Forte, Ambroxan, indole, hedione, sandelice,citrus oil, mandarin oil, orange oil, allylamyl glycolate, cyclovertal,lavendin oil, clary oil, β-damascone, geranium oil bourbon, cyclohexylsalicylate, Vertofix Coeur, Iso-E-Super, Fixolide NP, evernyl, iraldeingamma, phenylacetic acid, geranyl acetate, benzyl acetate, rose oxide,romilat, irotyl and floramat.

Preservatives

Suitable preservatives are, for example, phenoxyethanol, formal-dehydesolution, parabens, pentanediol or sorbic acid and the other classes ofcompounds listed in Appendix 6, Parts A and B of the Kosmetikverordnung(A Cosmetics Directive≅).

Perfume Oils

Suitable perfume oils are mixtures of natural and synthetic perfumes.Natural perfumes include the extracts of blossoms (lily, lavender, rose,jasmine, neroli, ylang-ylang), stems and leaves (geranium, patchouli,petitgrain), fruits (anise, coriander, caraway, juniper), fruit peel(bergamot, lemon, orange), roots (nutmeg, angelica, celery, cardamom,costus, iris, calmus), woods (pinewood, sandalwood, guaiac wood,cedarwood, rosewood), herbs and grasses (tarragon, lemon grass, sage,thyme), needles and branches (spruce, fir, pine, dwarf pine), resins andbalsams (galbanum, elemi, benzoin, myrrh, olibanum, opoponax). Animalraw materials, for example civet and beaver, may also be used. Typicalsynthetic perfume compounds are products of the ester, ether, aldehyde,ketone, alcohol and hydrocarbon type. Examples of perfume compounds ofthe ester type are benzyl acetate, phenoxyethyl isobutyrate,p-tert.butyl cyclohexylacetate, linalyl acetate, dimethyl benzylcarbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzylformate, ethylmethyl phenyl glycinate, allyl cyclohexyl propionate,styrallyl propionate and benzyl salicylate. Ethers include, for example,benzyl ethyl ether while aldehydes include, for example, the linearalkanals containing 8 to 18 carbon atoms, citral, citronellal,citronellyloxyacetaldehyde, cyclamen aldehyde, hydroxycitronellal,lilial and bourgeonal. Examples of suitable ketones are the ionones,α-isomethylionone and methyl cedryl ketone. Suitable alcohols areanethol, citronellol, eugenol, isoeugenol, geraniol, linalool,phenylethyl alcohol and terpineol. The hydrocarbons mainly include theterpenes and balsams. However, it is preferred to use mixtures ofdifferent perfume compounds which, together, produce an agreeableperfume. Other suitable perfume oils are essential oils of relativelylow volatility which are mostly used as aroma components. Examples aresage oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leafoil, lime-blossom oil, juniper berry oil, vetiver oil, olibanum oil,galbanum oil, ladanum oil and lavendin oil. The following are preferablyused either individually or in the form of mixtures: bergamot oil,dihydromyrcenol, lilial, lyral, citronellol, phenylethyl alcohol,α-hexylcinnamaldehyde, geraniol, benzyl acetone, cyclamen aldehyde,linalool, Boisambrene Forte, Ambroxan, indole, hedione, sandelice,citrus oil, mandarin oil, orange oil, allylamyl glycolate, cyclovertal,lavendin oil, clary oil, β-damascone, geranium oil bourbon, cyclohexylsalicylate, Vertofix Coeur, Iso-E-Super, Fixolide NP, evernyl, iraldeingamma, phenylacetic acid, geranyl acetate, benzyl acetate, rose oxide,romillat, irotyl and floramat.

Dyes

Suitable dyes are any of the substances suitable and approved forcosmetic purposes as listed, for example, in the publication“Kosmetische Färbemittel” of the Farbstoffkommission der DeutschenForschungs-gemeinschaft, Verlag Chemie, Weinheim, 1984, pages 81 to 106.These dyes are normally used in concentrations of 0.001 to 0.1% byweight m/m, based on the mixture as a whole.

EXAMPLES

Microemulsions were prepared to the formulations shown in Table 1. Tothis end, the oil-soluble constituents were heated to 70-80° C. andmelted, the water phase heated to the same temperature was partlyincorporated by stirring in the oil phase together with thewater-soluble constituents and the formulation was cold-stirred. Theviscosity of the formulations was determined by measurement with aBrookfield RVF viscosimeter with a Helipath TF spindle at 23° C./4r.p.m.

TABLE 1 Influence of aluminium-zirconium salt on the viscosity ofmicroemulsions based on sugar surfactants, comparison formulation C1 andformulations 1 to 4 according to the invention; quantities of theconstituents in % m/m C1 1 2 3 4  INCI Name Decyl Glucoside 15 15 15 1515  Glyceryl Oleate 8 8 8 8 8  Dioctylcyclohexane 11 11 7 — 6 Cyclomethicone 11 11 8 11 8  Dioctyl carbonate — — — 11 — Dicaprylylether — — 7 — 6  Aluminium Chlorohydrate 20 — — — —  AluminiumZirconium — 20 20 20 20  Tetrachlorohydrex GLY PEG-120Methylglucosedioleate — — — — 2  Water to 100 to 100 to 100 to 100 to100  Properties Appearance Clear Clear Clear Clear Clear  Viscosity(mPas) 6000 825000 875000 850000 2300000 

1. A highly-viscous microemulsion comprising: (a) a sugar surfactant;(b) an oil component; and an aluminium-zirconium salt, wherein thecomposition is transparent and has a Brookfield viscosity (RVTviscosimeter, 23° C. 4pm, TF Helipath spindle of at least about 100,000mPas.
 2. The microemulsion of claim 1 wherein the sugar surfactant ispresent in the composition in an amount of from about 1 to 40% byweight, based on the weight of the composition.
 3. The microemulsion ofclaim 1 wherein the sugar surfactant is present in the composition in anamount of from about 10 to 30% by weight, based on the weight at thecomposition.
 4. The microemulsion of claim 1 wherein the sugarsurfactant is present in the composition in an amount of from about 15to 20% by weight, based on the weight of the composition.
 5. Themicroemulsion of claim 1 wherein the oil component is present in thecomposition in an amount of from about 10 to 50% by weight, based on theweight of the composition.
 6. The microemulsion of claim 1 wherein theoil component is present in the composition in an amount of from about18 to 35% by weight, based on the weight of the composition.
 7. Themicroemulsion of claim 1 wherein the oil component is present in thecomposition in an amount of from about 20 to 25% by weight, based on theweight of the composition.
 8. The microemulsion of claim 1 wherein thealuminium-zirconium salt is present in the composition in an amount offrom about 5 to 40% by weight, based on the weight of the composition.9. The microemulsion of claim 1 wherein the aluminium-zirconium salt ispresent in the composition in an amount of from about 10 to 30% byweight, based on the weight of the composition.
 10. The microemulsion ofclaim 1 wherein the aluminium-zirconium salt is present in thecomposition in an amount of from about 15 to 20% by weight, based on theweight of the composition.
 11. The microemulsion of claim 1 wherein thesugar surfactant is selected from the group consisting of an alkyland/or alkenyl oligoglycoside, a fatty acid-N-alkyl polyhydroxyalkylamide, and mixtures thereof.
 12. The microemulsion of claim 1 whereinthe microemulsion has a Brookfield viscosity of at least about 400,000mPas.
 13. The microemulsion of claim 1 wherein the microemulsion has aBrookfield viscosity of from about 800,000 to 3,000,000 mPas.
 14. Acosmetic composition containing the microemulsion of claim 1, whereinthe composition is in gel or stick form.
 15. The microemulsion of claim1 comprising: (a) 1% to 40% by weight the sugar surfactant; (b) 10% to50% by weight the oil component; (c) 5% to 40% by weight of thealuminium-zirconium salt; (d) 0 to 10% by weight of a thickener; (e)water; and, (f) optionally auxiliaries, co-emulsifiers and additives;wherein, quantities of components add up to 100%.
 16. The microemulsionof claim 15 comprising: (a) 10% to 30% by weight of the sugarsurfactant; (b) 10% to 30% by weight of the oil component; (c) 10% to30% by weight of the aluminium-zirconium salt: (d) 1% to 8% by weight ofthe thickener; (e) water; and (f) optionally auxiliaries,co-emulsifiers, and additives.
 17. The composition of claim 15comprising: (a) 15% to 20% by weight of the sugar surfactant; (b) 15% to20% by weight of the oil component; (c) 15% to 20% by weight of thealuminium-zirconium salt; (d) 2% to 5% by weight of the thickener; (a)water; and (f) optionally auxillaries, co-emulsifiers, and additives.18. The microemulsion of claim 1 wherein the aluminium-zirconium saltcomprises a complex of amino acids with chlorohydrate salts of aluminiumand zirconium in an Al:Zr atomic ratio of from 3:1 to 10:1 and a totalmetal to chlorine atomic ratio of from 0.9:1 to 2.1:1.
 19. Themicroemulsion of claim 1 wherein the aluminium-zirconium salt comprisesat least one member selected from the group consisting ofaluminium-zirconium trichlorohydrate, aluminium-zirconiumtetrachlorohydrate, aluminium-zirconium pentachlorohydrate andaluminium-zirconium octachlorohydrate and complex compounds of thesesalts.
 20. The microemulsion of claim 18 comprising a partial glycerideco-emulsifier in a ratio of by weight of sugar surfactant to partialglyceride co-emulsifier of from 10:90 to 90:10.